Shouldered nut or bushing and method of making same



May 22, 1923. 1,456,177

w CRQCKETT SHOULDERED NUT, OR BUSHINGAND METHOD OF MAKING SAME Filed Jan. IO 1921 Jfl/ZOW 4 wMQ. $0M

-5 RMMPMW @mww Patented May 22, 1923.

WILLIAM F. ono'oxn'rr, OF CHICAGO, ILLINOIS.

SHOULDEBED NUT OR BUSHING- AND IMETHQD 0F IIIAKIN'GQSAIME. 7

Application filed January 10, 1921. Serial No. 436,054 it To all whom it may concern Be it known that l, lVILLLur P. Cnocnnrr,

a citizen of the United. States, residing at Chicago, in the county of Cool: and State of Illinois, have invented certain new and useful Improvements in shouldered Nuts orBushings and Methods Making S m of whicl the following is a specification.

Nuts or bushings are known, particularly for use in electrical fittings, having a threaded bore extending the major portion of the depth of the body, and having a shallow inwardly-extendingannular flange forming a. squared shoulder at the end of the threaded bore, such flange providing a reduced opening the external edge portion, or mouth, of which is rounded in crosssection. for electrical wiring, such a'bushinn" is used on the threaded end of a me tallic conduit where the latter enters an outlet box, switch box orthe lilre. the threaded bore screwingonto the end of the conduit, the square shoulder contacting with the square-cut end of the conduit, and the through opening); of the internal flange forming an effective continuation of the bore of the conduit, while the rounded mouth of said flange gives the requisite noncutting lip-surface to prevent the insulated wiring from being chafed or injured. Also the base of such bushing; forms a stop to be clamped against the inner wall of the outlet-box by the action of a nut that is threaded on the conduit and screwed up against the outer surface of theoutletbox wall.

Such shouldered bushings have commonly been made of one piece construction by casting the device in finalfform,; or by forging or swaging a blank. into the desired general form but, with a smooth cylindrical bore, and then tapping or threading said bore. Neither process produces wholly satisfactory results. The casting operation produces manypoorly-threaded and otherwise defective pieces and rarelyhdo the threads run full depth of the bore. forging process is relatively expensive and dillicult. Not only is it hard to thread the bore with, a full uniform thread, extending clear to the shoulder, but in practice it is expensive in that each piece must be individually threaded, and furthermore, theforging or swaging' of the blank is apt to result in such hardening of the metal that the threading operation will wholly or The partly fail. It is common and time-Wasteful experience to find on-- the market amaterial percentage of such bushings that will not screw home on the conduit and have to be discarded, oftentimes after so darnaging the conduit-threads, in the effort, as.

to increase the trouble-and time-waste.

One of the objects of my present invention isto provide an improvedshouldered nut or bushing of two-piece construction,

and a. method of making the same, insuring cheapness and uniformity of the vproduct and perfection of the requisitebore threadmg. t

In the drawing wherein I have shown my invention embodied in a bushing forthe electrical use above described, but Without intent to limit myself solely to such application of theinvention, Fig/l is a vertical section through an outlet box and conduit fragment 1n association with a,

bushing emboclying,.my invention; Fig. 2

is a. section on line 2 -2 of Fig. 1; Fig 3 is an extended view schematically representing. steps in the manufacture of myv invention; llig. 4 is a diagrammaticelevation with the parts in section showmg a final operation in thewmanufacture of the nut; and Fig: 5 is a section of a modified bushi119 embodying features of. my invention,

In the construction shown 10 indicates the body element of the bushing, uniformly threaded throughout itsbore-length, and 11 is shallow shoulder-forming collar, or ring; preferably externally. threaded, located in the mouth end of the body-bore and there permanently set or retained as by substantially immovable frictionalgrip brought about by forcing the parts together; r

In the manufacture of the article shown the bushing bodies are preferably stamped out of sheet metal of proper thickness into blanks, preferably of non-circular perimeter, such as the conventional hexagon shape shown, each with a smooth through done on astackv of blanks in asingle pass of the tapping tool, schematically suggested at 12 in Fig. 3. The blank thus proyided y be in Substance a deep-nut of ordinary form,

These bodies stand ready to receive the shoulder elements or rings 11, each of which, in its blank form is a square edged ring of a depth much less than that of the body blank, preferably externally threaded, and with a center opening substantially corresponding with or slightly less than the bore of the conduit with which the finished bushing is intended to be used. In making these ring blanks I preferably use tubular stock of suitable size, thread the tube externally throughout its length as indicated at 11 and saw off the ring blanks 11 of suitable depth, preferably utilizing for-this purpose a gang of parallel saws 13. A ring blank 11 is then screwed into the body blank 10 until their outer end surfaces are flush. In ordinary sizes of bushings this operation may most conveniently be done by the operator picking the ring blank up on the tip of the finger and screwing it into the bodyv blank until the thumb, exploring the joint, finds the parts to be flush. The assembled blanks arethen presented to a setting device, which may take the form of a simple punch member 16 and a coacting anvil 17, so that by a blow of the punch the collar ring is expanded radially and has its mouth rounded as at 10, the expansion of the ring setting it permanently in position in the body with a frictional grip that is (for all practical purposes of use) permanent or unbreakable. This operation may be done without distorting the thread 10 exposed in the free bore of thebody, and so it is insured that the free borethreading of the bushing is full and uniform throughout the intended conduit-receptive depth. Of course, superficial finishing, bylway of enameling or otherwise, is an optionalmatter following customary practice.

IVhile a smooth or non-threaded ring of sufliciently malleable material may be ex panded into the threads of the body, it is desirable to preliminarily thread the ring both to give facility of placing the ring accurately at the proper location in the body and to minimize the ring-expansion requirement.

Further, as shown in Fig. 5 the nut-blank may have its mouth-end milled out, before or after threading, to form a socket 10 and a ring l1 exteriorly smooth, may be seated in the socket and thereafter the parts forced together, permanently to set the ring, but, this, too, I deem much less advantageous than the construction first described.

While I have herein described in detail particular embodiments of mybushing invention and the method of making same, it will be understood by those skilled in the art that various changes in detail may be made without departure from the spirit of my invention within the scope of the appended claims. I claim:

1. An article of the character described, comprising a body internally threaded throughout its free bore and a shallow solid ring permanently engaging throughout its side-surface in the mouth or end of said body-bore.

2. As an article of manufacture, a'shouldered nut of the character described comprising a body having a uniform bore threaded throughout its bore-length and a shallow solid ring member externally threaded throughout its lengthand located. wholly within the body-bor e, the threads of the ring member engaging the end threads of the body member with a permanent frictional grip.

nently and substantially non-removably seated in the end threads of the body bore with the ends of the body and ring substantially flush.

4:. The method of making shouldered 3. An article of the character described,

bushings which consists in providing a body with a cylindrical bore threaded throughout its free length, blanking a shallow solid ring of size to enter the'mouth 0f the bore andexpanding the ring in the bore-mouth to engage the body throughout the full depth of the ring.

5. The method of making shouldered bushings which consists in providing a body having a cylindrical bore threaded througln out its length, blanking a solid ring having I an external thread to interfit with the bore thread, screwing the ring into the mouth of the body-bore and expanding the ring into the body to fix the parts permanently against displacement.

consists in making a deep body-blank with its bore uniformly threaded throughout, making a shallow ring element externally threaded to engage said bore, screwing the shallow ring into the deep body until their end surfaces are substantially flush and by a subsequent forming-action rounding the mouth of the ring and also expanding'the ring into permanent engagement with the body threads. I

Subscribed W nois, this, 10th day ofDecember 1920.

7 WILL A P. CR CKET T andsworn to at Chicago, I1li- I 6. The method ofmaking bushings which v 

